Prüfer’s Seasons
(Published on 23. May 2025, 22:34 by asimov.io)
Prüfer’s Seasons by Sebond
Rules:
Normal Sudoku rules apply.
There are four trees drawn in this grid. Digits cannot repeat on a tree. Each cosmetic cage, read clockwise, is the Prüfer encoding of the tree next to it (of the same color).
In other words:
- the cells of the tree which have only one neighbour (in that tree) are called leaves, and their only neighbour is called their father
- in the first cell of the cage, write the digit of the father of the leaf with the smallest digit among leaves
- then "remove" that leaf from the tree, and again in the second cell of the cage, write the digit of the father of the leaf with the smallest digit among leaves (in the new tree)
- continue until the tree has only 2 cells (this is why the cages are size N-2 for trees of size N)
Play in Sudokupad
Example here, also available on Sudokupad
Hope you enjoy it !
Might want to grab a pen and paper
Solution code: Column 9 digits from top to bottom
Comments
on 30. May 2025, 17:06 by asimov.io
small typo
on 25. May 2025, 15:12 by asimov.io
Added a precision that cages are only cosmetical
Updated difficulty from 4* to 5*
on 24. May 2025, 23:02 by tnop62830
Probably worth mentioning about the rules: Digits may repeat in cages
(this wasn't clear without looking at the example)
Very clever puzzle
